In our earlier U.S. Pat. No. 4,597,252, Ecuador Pat. No. PI-85-074, and U.K. Pat. No. 8313744 there are disclosed several embodiments of flower harvesting machines.
The present invention is directed to an improved harvester with a view to improving the mechanical harvesting techniques particularly in the construction of the plant engaging picking head.
For the pyrethrum industry to be viable in developed countries it has been found necessary to mechanize the harvesting of the pyrethrum flowers. Careful examination has revealed that the pyrethrins are contained in the flower head and the maximum yield is at the stage of the pyrethrum flower having matured beyond the bud stage to having four or more florets opened, but not to the stage of being overblown with the petals beginning to wither at which time the pyrethrins content is diminished.
This has led to the requirement of a harvester that can selectively harvest flower heads at the optimum stage of maturity while leaving buds for further development and later harvest. The need to harvest before the flowers become overblown (over mature) requires the harvester to be able to harvest a large area in as little time as possible.
As the flower heads contain the pyrethrins it is desirable to harvest only flower heads and not harvest stem or leaf material which results in higher transport and processing costs for both drying and extraction.
In harvesting pyrethrum, a conventional harvester travelling through the crop tends to push the flowers and stems over in a wave effect, ahead of and in the direction of movement of the harvester, causing the flowers on the underside of the bushes not to be picked. Excessive pressure bearing against the stem mass in an effort to pick all the flowers increases the ratio of unwanted stem and leaf material harvested.
The use of various devices to cut the flowers automatically causes a high percentage of stem material to be harvested. Devices to separate plants into individual rows for harvesting require the harvester to be accurately driven in line with rows and result in a difficult and slow method of harvesting, particularly in large fields with uneven slopes and contours.
A major problem occurring with the harvesting of high value crops such as pyrethrum is the large quantities of stem material which are also gathered during the harvest. This excess material causes several problems:
1. The additional weight which must be transported thus incurring additional freight costs. PA1 2. The additional drying which must be performed on the excess material, and PA1 3. The additional sorting and refining operations which must be performed in order to separate the flower heads from the stem material before the pyrethrum can be processed.
A principal objective of the present invention is to provide a mobile harvesting machine for flower heads in which the above mentioned problems are minimized to a significant extent, if not eliminated.